nitenpyram (562)
Insecticide
nitromethylene; neonicotinoid
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NOMENCLATURE
Common name nitenpyram (BSI, pa E-ISO)
IUPAC name (E)-N-(6-chloro-3-pyridylmethyl)-N-ethyl-N'-methyl-2-nitrovinylidenediamine
Chemical Abstracts name N-[(6-chloro-3-pyridinyl)methyl]-N-ethyl-N'-methyl-2-nitro-1,1-ethenediamine
CAS RN [120738-89-8]; [150824-47-8] (E)- isomer Development codes TI-304 (Takeda); CGA 246916 (Ciba-Geigy)
PHYSICAL CHEMISTRY
Mol. wt. 270.7 M.f. C11H15ClN4O2 Form Pale yellow crystals. M.p. 83-84 癈 V.p. 1.1 ?10-6 mPa (20 癈) KOW logP = -0.64 (25 癈, unstated pH) Henry 3.54 ?10-13 Pa m3 mol-1 (calc.) S.g./density 1.40 (26 癈) Solubility In water 840 g/l (pH 7.0, 20 癈). In chloroform 700, acetone 290, xylene 4.5 (all in g/l, 20 癈). pKa pKa1 3.1, pKa2 11.5
COMMERCIALISATION
History Reported by Minamida et al. (J. Pestic. Sci., 18, 41 (1993)). Under evaluation for crop protection use since 1989; introduced by Takeda Chemical Industries Ltd, and first launched in 1995. Also developed jointly with Novartis Animal Health Inc., for flea control. Manufacturers Takeda
APPLICATIONS
Biochemistry Agonist of the nicotinic acetylcholine receptor, affecting cholinergic transmissions in the insect central nervous system. Mode of action Systemic insecticide with translaminar activity and with contact and stomach action. Uses Control of aphids, thrips, leafhoppers, whitefly, and other sucking insects on rice and glasshouse crops. On rice, applied at 15-75 g/ha (foliar), 75-100 g/ha (dust) or 300-400 g/ha (soil treatment). Also for control of fleas on cats and dogs. Formulation types DP; GR; SP. Selected tradenames: 'Bestguard' (Takeda)
OTHER TRADENAMES
'Capstar' (for flea control) (Takeda, Novartis A H); 'Programa' (for flea control, Japan) (Takeda, Novartis A H); 'Takestar' (for flea control, Japan) (Takeda, Novartis A H)
ANALYSIS
Product and residue analysis by hplc. Details from Takeda.
MAMMALIAN TOXICOLOGY
Oral Acute oral LD50 for male rats 1680, female rats 1575, male mice 867, female mice 1281 mg/kg. Skin and eye Acute percutaneous LD50 for rats >2000 mg/kg. Very slightly irritating to eyes; not irritating to skin (rabbits). Not a skin sensitiser (guinea pigs). Inhalation LC50 (4 h) for rats >5.8 g/m3 air. NOEL (2 y) for male rats 129, female rats 53.7 mg/kg b.w. daily; (1 y) for male and female dogs 60 mg/kg b.w. daily. Other Not oncogenic (rats, mice). Not teratogenic (rats, rabbits). No effect on reproductive performance (rats). Non-mutagenic (4 tests).
ECOTOXICOLOGY
Birds Acute oral LD50 for bobwhite quail >2250, mallard ducks 1124 mg/kg. Dietary LC50 (5 d) for bobwhite quail and mallard ducks >5620 ppm. Fish LC50 (96 h) for carp >1000 mg/l. Daphnia LC50 (24 h) >10 000 mg/l. Algae EbC50 (72 h) for Selenastrum capricornutum 26 mg/l. NOEC (120 h) 6.25 mg/l. Worms LC50 (14 d) 32.2 mg/kg.
ENVIRONMENTAL FATE
Soil/Environment DT50 in soil 1-15 d, depending on soil type.
pymetrozine (660)
Insecticide
pyridine
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NOMENCLATURE
Common name pymetrozine (BSI, pa E-ISO)
IUPAC name (E)-4,5-dihydro-6-methyl-4-(3-pyridylmethyleneamino)-1,2,4-triazin-3(2H)-one
Chemical Abstracts name (E)-4,5-dihydro-6-methyl-4-[(3-pyridinylmethylene)amino]-1,2,4-triazin-3(2H)-one
CAS RN [123312-89-0] Development codes CGA 215944 (Ciba-Geigy)
PHYSICAL CHEMISTRY
Mol. wt. 217.2 M.f. C10H11N5O Form Colourless crystals. M.p. 217 篊 V.p. <4 ?10-3 mPa (25 篊) (OECD 104) KOW logP = -0.18 (OECD 107) Henry <3.0 ?10-6 Pa m3 mol-1 (calc.) S.g./density 1.36 (20 篊) Solubility In water 0.29 g/l (pH 6.5, 25 篊). In ethanol 2.25, hexane <0.001 (both in g/l, 20 篊). Stability Stable in air (OECD 113/DTA). Hydrolysis DT50 4.3 h (pH 1), 25 d (pH 5).
COMMERCIALISATION
History Reported by C. R. Fl點kiger et al. (Proc. Br. Crop Prot. Conf. - Pests Dis., 1992, 1, 43). Introduced in 1993 by Ciba-Geigy (now Syngenta AG). Manufacturers Syngenta
APPLICATIONS
Biochemistry Novel, unidentified biochemistry. Mode of action Insecticide selective against Homoptera, causing them to stop feeding. Uses Control of aphids and whitefly in vegetables, potatoes, ornamentals, cotton, deciduous and citrus fruit, tobacco, hops; both juvenile and adult stages are susceptible. Also control of planthoppers in rice. Application rates vary from 150 g/ha on potatoes to 200-300 g/ha on ornamentals, tobacco and cotton; 10-30 g/hl on vegetables, fruit and hops. Formulation types DP; GR; WP; WG. Selected tradenames: 'Chess' (Syngenta); 'Plenum' (Syngenta)
OTHER TRADENAMES
'Endeavor' (Syngenta); 'Fulfill' (Syngenta) Discontinued names: 'Sterling' * (Ciba-Geigy)
ANALYSIS
Residue determination by hplc and u.v. detection. Details available from Syngenta.
MAMMALIAN TOXICOLOGY
Oral Acute oral LD50 for rats 5820 mg/kg. Skin and eye Acute percutaneous LD50 for rats >2000 mg/kg. Non-irritating to the skin and eyes (rabbits). Not a skin sensitiser to guinea pigs. Inhalation LC50 (4 h) >1800 mg/m3 air. NOEL (2 y) for rats 3.7 mg/kg b.w. daily. ADI 0.03 mg/kg b.w. Other Non-mutagenic in 5 assay tests including the Ames test. Toxicity class WHO (a.i.) III
ECOTOXICOLOGY
Birds Acute oral LD50 for bobwhite quail, mallard ducks >2000 mg/kg. LC50 (8 d) for bobwhite quail >5200 ppm. Fish LC50 (96 h) for rainbow trout and common carp >100 mg/l. Daphnia LC50 (48 h) 87 mg/l. Algae LC50 (72 h) for Scenedesmus subspicatus 47.1 mg/l; LC50 (5 d) for Selenastrum capricornutum 21.7 mg/l. Bees LD50 (48 h) (oral) >117 mg/bee; (contact) >200 mg/bee. Worms LC50 (14 d) for Eisenia foetida 1098 mg/kg soil. Other beneficial spp. Harmless to Aleochara bilineata, Poecilus cupreus, Typhlodromus pyri, Orius insidiosus, Aphidius colemani, Aphidius matricariae, Chrysoperla carnea.
ENVIRONMENTAL FATE
Animals Quickly and efficiently eliminated (mainly via excreta) and extensively metabolised in all species tested (rats, farm animals), without accumulation in most major animal food products. The metabolic pathways are similar for all species. Pymetrozine is the relevant residue for assessing the consumer exposure to treated animal food products. Plants The basic degradation steps are similar in all investigated crops; pymetrozine is the only relevant compound for residue definition. Soil/Environment In soils, very rapidly and strongly adsorbed, with low mobility and low leaching potential. Soil DT50 2-69 d, DT90 55-288 d. Rapidly degraded in slightly acidic or sunlight-exposed surface water; DT50 in surface water (typical value) 7 d. Slightly volatile. Efficiently removed by direct photolysis and photochemically induced oxidation.